In a microchemical system, a very small amount of samples needs to be detected and analyzed with high sensitivity after chemical treatment has been performed using a microwell, a microchemical chip and an electrophoretic chip. Until now, in the microchemical system, there has been often used a detection method using fluorescence and phosphorescence.
As shown in FIG. 9, as a conventional technique, for example, there has been known a method of cause a plurality of laser beams to travel through a space to irradiate a measurement region therewith at the time of detecting fluorescence and phosphorescence generated from a sample flowing through a microchemical chip.
This method, however, some distance is required in order to cause the laser beams to travel, extending the laser beam by diffraction, which the size of a focal point cannot be reduced to substantially 0.5 mm or less, resultantly, a minute region cannot be detected. Furthermore, this method adjusts a position irradiated with the laser beams by adjusting the angle of a mirror or the like, however, some distance is required in order to cause the laser beams to travel, so that a subtle angular displacement occurring at the time of adjusting the angle causes a positional displacement, making it difficult to adjust the position and there is a problem that the method is susceptible to vibration.
This method is capable of irradiating the same minute region with a plurality of laser beams, however, as stated above, it is basically difficult for the method to adjust the position, requiring a very complicated optical system. When a plurality kinds of substances generating fluorescence or phosphorescence at a plurality of points are simultaneously measured, this method scans laser beams to quasi-simultaneously measure the substances. The quasi-simultaneous measurement, however, needs a more complicated optical system. In addition, a short irradiation time significantly reduces sensitivity.
As shown in FIG. 10, as a method of solving the problem, there has been known a method in which a laser beam and fluorescence (or phosphorescence) are propagated thorough an optical fiber and the laser beam is focused to a measuring region by a microlens to detect the fluorescence (phosphorescence) (refer to, for example, Japanese Laid-Open Patent Publication (Kokai) No. 2005-30830).
However, the above method in the conventional art causes the following problem at the time of measuring concentration and state of a plurality kinds of substances generating fluorescence or phosphorescence in solution.
In the case where the above substances are irradiated with excitation light having a different dominant wavelength to excite the substances and fluorescence (phosphorescence) having a different dominant wavelength generated from solution thereby is detected, the method in the conventional art requires two detection systems of FIG. 10 as shown in FIG. 11. In the system, the focal position of each excitation light is displaced due to a width of the lens used for focusing. Using a small lens such as a microlens for focusing displaces a focal position by 2 mm to 3 mm. For this reason, the detection system shown in FIG. 11 cannot be used to detect fluorescence (phosphorescence) in solution containing the above substances which is contained in the same micro well.
The object of the present invention is to provide a detection system capable of simultaneously detecting a plurality of fluorescences or phosphorescences having different dominant wavelengths and generated from a minute region and a probe therefor.